From their site: This API provides geo-coordinates, city, state, epoch, runway and other information for about 40,000 airports. It is the largest database of airports available online. Add data about airports to your application utilizing the AirportInfo library. Get IATA Code, Landing Facility Type - Airport, Heliport etc, Latitude, Longitude, Elevation in Foot MSL, Magnetic Variation and Direction, and PilotOutlook URL for more information.
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Well if you consider USA == Worldwide then this service might be ok. It does not know the IATA codes for Frankfurt or Berlin nor Munich. Usable only for american's who do not want to leave their country.